Certainly, not all Christians are pacifists, and not all pacifists are Christians.
But, to my mind, pacifists choose to not fight back by definition, or that would be violence, so their prolonged existence is only possible because other social mechanisms hold back violence which would destroy them. Interaction with these mechanisms may be the point of holding a pacifist position: say, a monk or a nun may have a higher moral authority because of a declared personal abstinence from any violence, and hence indirectly incentivize lay people to protect them.
Of course there are people who call themselves pacifists but admit a right for self-defense, but only not organized or military; such a position again is only possible when someone else would partake in a defensive warfare and protect them.
Abstaining from aggression while being ready and willing to respond to aggression with full force, lethal when required, looks to me like the most logical "lawful good" position. It has a chance to produce an equilibrium when multiple parties live in peace for a long time, and any violent deviations are quashed.
"But, to my mind, pacifists choose to not fight back by definition, or that would be violence, so their prolonged existence is only possible because other social mechanisms hold back violence which would destroy them."
Again, this is a valid, but narrow definition of pacifism. One that is more often found in misguided Christians who take Mathew 5:39 literally than serious scholars. The willingness for self defense does not preclude pacifism at all.
A good example is Mahatma Gandhi who is widely recognized as a pacifist, yet argued that it is better to fight than to be a coward in the face of injustice.
Mr Gandhi was smart and used the social mechanisms of the British empire. The enlightened citizens of the metropoly, with their heightened sense of fair play, would strongly disapprove of police / army brutality towards peaceful and outspoken protesters.
The classical thought experiment replaces the British Raj with a German, or, better yet, Soviet occupation administration. With them, peaceful protests spectacularly won't work, and would be insane to try.
(Right after the independence was achieved, the land descended into a brutal war that claimed 20M dead, the death toll similar to that of WWI.)
say, a monk or a nun may have a higher moral authority because of a declared personal abstinence from any violence, and hence indirectly incentivize lay people to protect them.
To take that a step further, making the pacifist definition even narrower, wouldn't such a pacifist be a hypocrite?
Abstaining from violence at the expense of others putting themselves in harms way to protect them?
Shouldn't they try to make these "lay people" abstain from violence as well?
But then who is left to defend the pacifists?
Does that mean in the face of outside aggressors all pacifists will die soon or live horrible lives under oppression from the aggressor?
Which I guess is OK for them if they believe that something better is available for them in 'heaven'?
Not necessarily, or even not likely a hypocrite. If keeping the ritual cleanliness is important for the monk's job, that is, having a better contact with the divine for the benefit of those around him, this is just specialization. The monk likely also abstains from other things, like eating meat, or having sex, which is a part of the same self-sacrifice for the sake of his service.
It would be hypocrisy if the monk commanded others to fight instead of him, while also declaring that he finds violence morally debasing and thus unacceptable for himself. But I don't think that laypeople would respect such a figure.
But not even all Christian scholars subscribe to that definition, let alone pacifists in general. Many pacifists are perfectly ok with self-defense.